A power converter includes an input circuit that receives DC input power and creates high frequency pulses. A transformer transforms the high frequency pulses into at least two sets of transformed pulses having alternating and opposite polarity. An output circuit connected to the transformer includes a plurality of switches for blocking undesired pulses. A controller controls the switches so that they are on except when blocking undesired pulses, so that a continuous current path is provided through the output circuit.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A DC to AC power converter comprising: an input circuit for receiving input power and creating high frequency pulses of varying width; a transformer for transforming the high frequency pulses into a first series and a second series of transformed pulses of alternating first and second polarity, the transformer comprising a primary winding and a secondary winding, the primary winding coupled to the input circuit; an output circuit including a plurality of switches for providing an AC output, the output circuit coupled to the secondary winding; and a controller for controlling the switches to provide a continuous current path through the output circuit, wherein the controller controls the switches such that each switch is on except when blocking a pulse of the second polarity during a first half cycle of the AC output and when blocking a pulse of the first polarity during a second half cycle of the AC output.
2. The power converter of claim 1 wherein the secondary winding of the transformer has a center tap and first and second legs.
3. The power converter of claim 2 wherein the output circuit includes a coil, a first switch coupled between the first leg and a first end of the coil, and a second switch coupled between the second leg and the first end of the coil.
4. The power converter of claim 3 wherein the output circuit includes a first output terminal coupled to a second end of the coil, and a second output terminal coupled to the center tap.
5. The power converter of claim 4 wherein the output circuit includes a capacitor coupled between the first and second output terminals.
6. A power converter comprising: an input circuit; a transformer comprising a primary winding and a secondary winding with a center tap, wherein the primary winding is coupled to the input circuit, and wherein the secondary winding comprises a first portion and a second portion, the secondary winding producing in the first portion and the second portion simultaneous pulses of opposite and alternating polarity with respect to the center tap and varying pulse width; an output circuit for providing an AC output comprising: a first AC switch coupled to receive pulses from the first portion; a second AC switch coupled to receive pulses from the second portion; and a coil coupled to the first switch and the second switch to receive pulses passed by the first and second switches and produce the AC output; and a controller that controls the first switch and the second switch such that each switch is on except when blocking a pulse of an unwanted polarity, so that during a first half cycle of the AC output only pulses of a first polarity are passed by the first and second switches and so that during a second half cycle of the AC output only pulses of a second polarity are passed by the first and second switches.
7. The power converter of claim 6 , wherein the controller comprises: a primary controller; an input controller coupled between the primary controller and the input circuit; and an output controller coupled between the primary controller and the output circuit.
8. The power converter of claim 6 , wherein the primary controller provides an ON TIME control signal to the input controller and to the output controller to synchronize the input controller with the output controller.
9. The power converter of claim 7 , wherein the output controller operates the first switch and the second switch to provide a constant path for current flow through the output circuit.
10. The power converter of claim 7 , wherein the output controller further comprises: an ON pulse generator; an ON pulse delay coupled to the ON pulse generator; an OFF pulse generator; an OFF pulse delay coupled to the OFF pulse generator; a decoder coupled to the ON pulse delay and the OFF pulse delay; a first driver coupled to the decoder; a first pulse transformer coupled between the first driver and the output circuit; a second driver coupled to the decoder; and a second pulse transformer coupled between the second driver and the output circuit.
11. The power converter of claim 6 , wherein the output circuit further comprises a capacitor coupled to the coil.
12. A method of converting power, the method comprising: receiving DC power; converting the DC power into high-frequency pulses of varying width; transforming the high-frequency pulses into a first series and a second series of transformed pulses, each series comprising alternating desired pulses and undesired pulses; selectively passing desired pulses and blocking undesired pulses by maintaining a first switch and a second switch in an on condition except when blocking undesired pulses, wherein during a first half cycle the desired pulses have a first polarity and the undesired pulses have a second polarity, and during a second half cycle the desired pulses have a second polarity and the undesired pulses have a first polarity; and converting the desired pulses received from the first and second switches into an AC output.
13. The method of claim 12 , wherein an output controller controls the first switch and the second switch.
14. The method of claim 12 , wherein a primary controller provides an ON TIME control signal to synchronize an input controller that controls converting the first signal into high-frequency pulses with an output controller that controls the first and second switches.
15. A power converter that converts DC input power to AC output power, the power converter comprising: an input circuit for receiving the DC input power and creating high-frequency pulses of varying width; a transformer for transforming the high frequency pulses into a first series and a second series of transformed pulses of opposite and alternating polarity; an output circuit for receiving the first and second series of transformed pulses, the output circuit comprising a first AC switch for controlling the passage of pulses of the first series and a second AC switch for controlling the passage of pulses of the second series; and a controller for controlling the first AC switch and the second AC switch to create the AC output signal and to maintain at least one of the first switch and the second switch on at all times to provide a path for continuous current flow through the output circuit during operation of the power converter, the controller selectively controlling the first and second switches to pass only pulses of the first and second series having a first polarity during a first half cycle and only pulses of the first and second series having a second polarity during a second half cycle.
16. The power converter of claim 15 , wherein the output circuit further comprises a low-frequency continuous current coil coupled to the first switch and the second switch.
17. The power converter of claim 15 , wherein the output circuit further comprises a capacitor coupled to the coil.
18. The power converter of claim 15 , wherein the first switch and the second switch each comprise back-to-back MOSFETs.
19. The power converter of claim 15 , wherein the controller comprises an output controller for controlling the first switch and the second switch, the output controller comprising: an ON pulse generator to provide an ON pulse; an ON pulse delay to delay the ON pulse; an OFF pulse generator to provide an OFF pulse; an OFF pulse delay to delay the OFF pulse; a decoder to receive the ON pulse and the OFF pulse and to select whether to adjust a state of the first switch or the second switch; a first driver for receiving the ON pulse and the OFF pulse for the first switch; a first pulse transformer for providing a first control signal to the first switch; a second driver for receiving the ON pulse and the OFF pulse for the second switch; and a second pulse transformer for providing a second control signal to the second switch.
20. A power converter comprising: an input circuit; a transformer comprising a primary winding and a secondary winding with a center tap, wherein the primary winding is coupled to the input circuit, and wherein the secondary winding comprises a first portion and a second portion, the secondary winding producing simultaneous pulses of opposite and alternating polarity; an output circuit comprising: a first switch coupled to receive pulses from the first portion; a second switch coupled to receive pulses from the second portion; and a coil coupled to the first switch and the second switch to receive pulses passed by the first and second switches; and a controller that controls the first switch and the second switch such that each switch is on except when blocking a pulse of an unwanted polarity, wherein the controller comprises: a primary controller; an input controller coupled between the primary controller and the input circuit; and an output controller coupled between the primary controller and the output circuit.
21. The power converter of claim 20 , wherein the primary controller provides an ON TIME control signal to the input controller and to the output controller to synchronize the input controller with the output controller.
22. The power converter of claim 20 , wherein the output controller operates the first switch and the second switch to provide a constant path for current flow through the output circuit.
23. The power converter of claim 20 , wherein the output controller further comprises: an ON pulse generator; an ON pulse delay coupled to the ON pulse generator; an OFF pulse generator; an OFF pulse delay coupled to the OFF pulse generator; a decoder coupled to the ON pulse delay and the OFF pulse delay; a first driver coupled to the decoder; a first pulse transformer coupled between the first driver and the output circuit; a second driver coupled to the decoder; and a second pulse transformer coupled between the second driver and the output circuit.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 19, 2003
February 21, 2006
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